void main(){
    vec4 worldPos = worldMatrix * vec4(0.0, 0.0, 0.0, 1.0);
    vec3 dir = worldPos.xyz - cameraPos;
    float distance = dot(cameraDir, dir);
    float m11 = projectionMatrix[1][1];
    float halfHeight = (viewport.w - viewport.y) * 0.5;
    scale = ((distance/halfHeight) * spriteHeight)/m11;
}
